Yes I hate it when it goes on for like ...hmmmm maybe more than forty something to fifty eps. My only exception was with Yu Yu Hakusho. I kept on enjoying that up to the 112th episode. I really dislike endless shows that have hundreds of episodes. Usually they're crap by that point.

The only way an anime can have too many episodes is if it's run out of story and they're just throwing stuff out there just because. An anime can be 26 episodes and have too many episodes if the story should've been wrapped up in 13. But, I think of the long runners you're referring to, the only one that I think went too long was Bleach. Considering the garbage arc after Ichigo and Aizen's final battle, it definitely should've ended with Ichigo and Aizen's final battle.

Other long runners I still thoroughly enjoy, such as One Piece, Naruto Shippuden (When not cramming it with filler) and Gintama.

The usual 12 or 24 is perfect for me. Anything longer than that and it seems like the story is too long-winded or a sign of filler. Of course if a show has multiple seasons/series I'd make an exception.

These days I don't have the patience to watch an anime with over 50 episodes, but the one exception to this rule for me is Sailor Moon, since I grew up with the original 200 eps. Aside from the fact that the first half of the Romance season is filler (series-progressive filler, but still filler), that's the one anime I can handle that is over 50 eps.

So, I've never watched One Piece, Bleach, Naruto, HxH, or Gintama due to the sheer number of episodes. I don't read the manga counterparts, either. They're simply too long for me.

12-50 episodes is plenty for me, but most series I watch fall into the 12-26 number.

There are shows over there that have 2,000+ episodes. I mentioned this in another thread, I think. Maybe it was this one? Can't recall. Yes, I will say that some anime just simply have too many episodes that it gets ridiculous. I had the same problem with Lost and other drawnout long TV shows.

Not really. those 12 episodes anime are pissing me off. When they put up a nice one that i enjoyed, i wish they go on for another 12 / 13 / 14 episodes. 25 Episodes anime are usually good for me.
But i do agree that some animes are just dragging on forever like Naruto ( Welp i stopped watching it so not sure what is happening right now )

Long animes suck only if the episodes are un-entertaining, while Bleach and Naruto are filled with uninteresting unwatchible fillers, One Piece fillers are more comedy oriented and therefore, more pleasant to watch, as for the actual show, the show itself has always maintained a sense of balance in quality.

Naruto is definitely too long and doesn't have much to support it's length because it constantly banks on Sasuke Vs Naruto, which is why I want it to end

One Piece however is still very pleasant to watch and doesn't have much of a reason to stop because it's fun

Bleach is also very long and nothing really holds up the structures for why it should continue considering it doesn't have a plot. It's also the same for Pokemon and DBZ, but One Piece does it correctly.